Elements of truth - Moseley, Bohr, recognition and teaching.

[epenguin]

There is no longer a history section in PDF, but this is not suitable for any speciality forum.

Just yesterday*, as usual a step ahead and with uncanny prescience, I was recommending a student to familiarise himself with Moseley's law as reinforcement and more in the learning of atomic physics and chemistry to do with the periodic table tendencies #6 and a little refreshing my fading memory mugging it up myself. Whaddayaknow, today* in The Times was published the following appeal, to counteract perhaps the fading memory of the scientific community. (*But then PF was down so this had to wait a day.)

Element of truth

Sir, The discovery last December of four super-heavy chemical elements re-awakened worldwide interest in the periodic table, one of the great organising themes of science. Last year also marked the centenary of the death of the scientist Henry Moseley in the Gallipoli campaign. In a brief but breathtaking research career just before the outbreak of the Great War, Moseley discovered that the atomic number of an element was the fundamental property ordering the periodic table. In these days of multi-billion dollar projects to probe the nature of matter, we recall the words of the 1923 Nobel laureate Robert Millikan on Moseley’s contribution: “A young man 26 years old threw open the windows through which we could glimpse the sub-atomic world with a definiteness and certainty never dreamt of before.”

Despite his pivotal role in shaping the modern periodic table, no chemical element has ever been named after Moseley. The time has now come to honour his contribution by naming one of the new elements after him.

Professor Eric Scerri, UCLA; Professor Russell G Egdell, University of Oxford; Professor Roald Hoffmann, Cornell University; Professor Friedrich Hensel, University of Marburg; Professor Sir John Meurig Thomas, FRS, Cambridge University; Professor Peter P Edwards, FRS, University of Oxford
Related to this is an issue that has been commented from time to time on this forum. This is the strongly expressed dislike of some physicists for any place for the Bohr theory of the atom in teaching, usually justified by their fear that students once exposed to it are doomed to everlasting misunderstanding, heresy, and damnation of their souls. But it was by this theory that Moseley was able to explain his findings, and through that the general structure of atoms.

The way I see it is: natural sciences have two different though intertwining and inseparable strands: Discovery of the constitution of the world on the one hand, and its dynamics on the other. The professor of pure mathematical physics might be, I suggest, overemphasising the latter, the correct dynamical laws and concepts and their formulations, taking too much for granted the present understanding of the former, atomic structure. The Bohr model is relevant not just to (quantum) dynamics and its laws, but to how the first ever experimentally based picture of the constitution and structure of atoms in general, far from clear at the time, was arrived that via Mosley's work. Perhaps because of their different situations along the constitution-dynamics axis chemists and those in related sciences may have more acceptance of this than do pure mathematical physicists?

 

[Eric Scerri]

Thanks for broadcasting our letter to the Times about Moseley.
However, the question of how much Moseley's work supported Bohr's theory is not such a foregone conclusion as implied above.

Alternatively perhaps the author of the above piece might care to elaborate.

I for one believe that Bohr's model should be taught in chemistry courses. It is important for students to see how a model featuring precise and deterministic orbits gave way to a very different model involving indeterministic paths within orbitals rather than orbits. I also think that the historical dimension is valuable in teaching and learning science. Those that favor the eradication of the Bohr model do students a dis-service.

Eric Scerri
www.ericscerri.com

 

[Astronuc]

Moseleum?

I wish I could go back 40+ years ago, but we probably discussed Bohr and Moseley in Chemistry class.

I'd like to see stronger ties between Mathematics, Physics and Chemistry in primary education. I took two years of Chemistry in High School, and I would have loved two years of Physics. We did start using differential equations at the end of my first year of Chemistry. I think our high school was the only public school with such a program. Two other schools with similar programs were private schools, and we used to compete with them at math and science contests.